Desulphurizing oils



Patented June 8, 1 926. I

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ERNST M. JOHANSEN, OF FALL RIVER, MASSACHUSETTS, ASSXGN'dR TO THE ATLANTIG BEE-TRYING COMPANY, 015 EHILADELPHIA, EENNSYLVA'NIA, A CQRPORA'KIUN OF FERN SYLVANIA.

Ito Drawing. Application filed may 1,

My invention relates to a method of treating oils, as petroleum, shale oil and other mineral oils, and more particularly their products, to remove or reduce their sulphur" eontent.

My invention will be described more particularly with regard to the treatment of petroleum, and particularly its distillates or products, as gasolene, naphthaand kerosene or lamp .oil, which, for brevity, will be termed light distillates.

Light distillates of the character referred to often contain so-called sour sulphur, consisting of compounds of sulphur of uncertain or unknown composition, and corrosive or free or elementary sulphur in solution.

Mineral oils often contain sulphur, free or eol'nbined in a large number of compounds. These compounds and free sulphur have a corrosive effect on copper,determinable by the well known copper dish test (technical paper, Bureau oi Mines, No. 323, page 823, Specification for testing petroleum products and methods for testing), in accordance with which the oil is evaporated to dryness in a copper dish and presence or absence of black corrosion observed. These free and combined sulphur bodies which so etlect corrosion are for brevity herein and in the appended claimslermed corrosive sulphur.

Certain other compounds of sulphur react to the well known doctor test (aforesaid technieal paper, page 83), which consists' in shaking; the oil with a water solution of sodium plumbite and powdered sulphur. These compounds give a discoloration of the solid sulphur and/or oil, and the oil containing them. is' known as sour. These compounds are for brevity herein and in the appended claims termed sour sulphur. i

In :urcordance with my invention, with the oil to be treated and containing sour sulphur or corrosive sulphur, or both, is blended an oil, preferably of substantially the same character, containing corrosive sulphur or sour sulphur, or both, and to the mixture is applied an aqueous solution of sodium plumbite, or equivalent, which reacts with the sour sulphur compounds to efiect products with which the corrosive sulphur reacts.

tt urther in accordance with my invention,

, DESULPHUHIZING QELS.

1923. Serial No. 635,967.

An oil or distillate containing soursulphur, such, for example, as crude naphtha,

may be subjected to any usual and customary preliminary treatment, as'by washing with water or dilute solution of sodium hydroxide, to remove hydrogen sulphide. With the oil or distillate is thereafter mixed or blended a natural or artificial solution of corrosive or free sulphur in an oil, prefer ably of the character of or similar to that to be treated. The mixture is thereafter agitated in the presence of a solution of sodium plumbite, or equivalent soluble alkali-metal plumbite, and allowed to settle.

Upon removal of the resultant precipitate and the aqueous solution, there remains it treated oil, which is practically clear afterthe aforesaid treatment, which may then be washed, as with water, and thereafter sub jected to steam distillation. When crude naphtha or gas naphtha has been treated as described, the steam distillation yields a sweet gasolene, one substantially free. of sour sulphur, and there remain bottoms of blending naphtha, lamp oil, etc, wh'chare also sweet or substantially free of sour sulphur.

The free or elementary sulphur used in the removal of sour sulphur may be used as such by dissolving the same in an oil, prefer-- ably an oil of the character under treatment. That is, in treating a gasolene, naphtha or lamp oil the tree or elementary sulphur as such is preferably dissolved in gasolene, naphtha, or lamp oil, whereby the character of the oil treated will not be substantially modified. For example, in treating lamp oil for removing sour sulphur in accordance with this method, if there should be utilized a free or elementary sulphur in solution in gasolene, gasolene would be present in the treated lamp oil, undesirably lowering the dash point of the lamp oil.

'lhe artificial solution of free or elementary sulphur in oil of the character re terred to may readily be produced in any suitable way. For example, sin-excess at Hit free or elements. y sulphur may be added to course to a circulatingpuiup. After agitalion the excess sulphur readily settles from lbe clear oil solution, which. Will contain from approximately to 0.8 per cent of (lissoli-ccl free sulphur I In lieu of utilizing an artificially prepared solution of iree or elementary sulphur, there may be useol an oil or disi'ill-(u'e containing corrosive free sulphur Such an oil or distillate serves as a. solution of Free sulphur, which may added to the oil or distillate to be treated.

In both cases, Whether an artificial or natural solulion of'free sulphur in oil utilized, ii, is preilerrccl that the operation or ii'ea'cmeutbe coi'itinuous one, as distinguished from belch operation, in that to a. continuously flowing stream of oil or distillate so be created with plumbite solution there be continuously added, in proper proportion, a solution or free or elementary sul'.

phur in oil.

By utilizulion of u solution oi. free or ele memory sulghur in oil, as distinguished from the addition of free or elementary powclereo. sulphur us such, the reaction of the free sulphur solution with. iille compounds formed by plumhite is practically instantaneous, pcrmitiziug either coniinuous or butch operation, though continuous operation gpceferrecl, and preventing en excess of free or elementary sulphur in the erected. oil. Accordingly, by the use of 9. solution of eleitoeuiair sulphur in oil, in lieu of elemental-y sulphur as such, the oil which has been tr ated for removal of sour sulphur will not when finished; contain substantial amounts of elementary sulphur, and will therefore no: be an oil which con tains corrosive sulphur.

The ui'nouu'l; or rate o'l edciiiiou of oil C033- sulphur in solution may iced by e preliniinury lest which be ifollowsr-'lhe oil containing sour lpl'iur may be, for example, naphtha "om standard White distillate. 1100 cubic liimelic of the naphtha may be 2., loci for, soy, hhrce minutes with cubic ccuiii'nel crs of sodium plumbite solution. The addition oi. the sodium plurnhite causes the 111s uoplr'rho. to partake of a dork, orange color. filler the plumbite treatment ihc niixlure is allowed to settle, and of the naphtha cubic ccn timclcrs are (token, illlll there is gradually added thereto from burci'ie a siiiutiou of elementury sulphur in was naphtha. 1 Breaking or completion of IilCiiOll 3'30 lorn i pi.'ec' gil.ele may take place .uitcr adding 1.? .ul c centimeters oi lhc elementary sulphur ll 'hcu becomes known than? I 'iiucicrs of ihe sulphur si'ilui'iou will be sufiicicni for url- )l soliu ou. '7

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mixture with 1000 cubic ccuiiineters oi the gas naphtha to be treated with pluu'ibite solution.

Vi hile the quantities above referred to are followed in determining the amount; of solu tion of elementary sulphur in oil to be uibilized in a large Way in plant yorectice.

My invention is applicable also to the treatment of an oil or distillate containing free or corrosive sulphur, by adding thereto in proper proporlious, (.lOiQl'IllllllLlJlt! as in the foregoing example, an: oil or distillate, preferably of the some character us Lhc oil to be treated, containing sour sulphur, to be agitated in the presence of sodium plumbii c or equivalent solution. The compounds formeclby the reaction of. the pluinbil'e with the sour sulphur compounds then react Willi the free or elementary sulphur in the oil or distillate-lo be treated, causing precipitulc which is settled out leaving the oil substantiully free of corrosive or elemeiiicry sulphur, and also sweel; or substantially free sour sulphur.

By the methods hcreiubefore described, the oil containing lhe free or eleuici'itory sulphur max be either the or the oil to be and the oil containing sour sulphur, may be either the oil to be treated or the reagent.

In both cherociiers of treatment above do scribed, and particularly when there treated or utilizecl as-reagent an oil naturally containing free or corrosive sulphur, boil: oils at least in port clesulphurizecl, one yielding up free or elementary sulphur, and the other sour sulphur, the resultant mixture of oils being sweet or free from sour sulphur compounds and also non-corrosive in the sense that it is free of corrosive or free sol phur.

Accordingly, by m invention the different types of oil common y occurring in refinery practice, one containing sour sulphur (willpounds and the other eleme'nlury sulphur, may be utilized to treat or modify each other to clesulphurize boib.

if the amount of free or corrosive sulphur present in the oil or distillate containing also, the sour sulphur compounds is small or insuliicicol to break or react with all of the .compoiuuls ro be "formed by the plumbite solution, additional elcmcnmry sulphur is milled-in the form of a. solution of clomeutei'y sulphur in oil, preferably zin oil of the character under treatment. By the addition 02 the sulphur solution the (lurk colored compoumjls ioruieiii upon addition of the plumbiie solution will lie completely broken, that is, the reaction will be compleic, producing u. precipitate which settles out, yielding an oil or distillate which is sweet or free of sour il COIHPOHZ'KlS, and also free oi corrosive or free sulphur.

relatively small, the same procedure may be 6 If, however, the oil or distillate contains an excess of elementary or free sulphur, the breaking or reaction of or with the compounds produced by reaction of the plumbite solution with the sour sulphur compounds will be complete, and the resultant oil will be sweet or free of sour sulphur compounds, but will still contain corrosive or elementary sulphur. In this case the excess of corrosive or free sulphur may beremoved by adding in proper quantity to the oil to be treated an oil containing sour sulphur compounds. Or they may be blended with the oil containing sour sulphur compounds and an excess of elementary sulphur, before treatement with the sodium plumbite solution. an oil of the character first above referred to, to wit, one containing insufiicient elementary sulphur. The mixture of the'oils of the two types will be made in such proportions that the amount of elementary sulphur is just sufficient completely to break or react with the compounds to be formed by reaction of the sodium plumbite solution with the sour compounds resent.

In the case of gasolenes erived, as by compression methods, from still gases resulting from destructive distillation of petroleum there is available in the refinery a material containing considerable amounts of free or elementary sulphur, which may be utilized in the ways hereinbefore described for removing sour sulphur and at the same time eliminating the free sulphur of the reagent solution. So far as I am aware, it has heretofore been the practice in refineries to remove the tree sulphur from the gasolenes from still gases by redistillation, a process entailing considerable losses. However, in accordance with my invention, by using such gasolenes from still gases as reagentsolution, a gasolene containing sour sulphur may be mixed with gasolenes from still gases containing elementary sulphur, with the result that both gasolenes are desulphurized, upon addition of plunibite yielding a mixture of gasolenes free of both sour sulphur and corrosive sulphur.

It shall be understood that my invention is not limited in its application to any particular method of treating a crude naphtha, gas naphtha or other crude distillate. For example, while I have hereinbefore referred to. the washing of the'crude distillate with water or dilute solution of sodium hydroxide, to remove hydrogen sulphide, it will be undcrstood that the crude distillate or gas naphtha may be treated with sulphuric acid,

followed by washing with water and/or hydroxide solution, and then the agitation with sodium plumbite solution may be efsense to include sodium 1plumbite and equivalent soluble alkali-meta What I claim is:

1. In the treatment of mineral oil, the method which comprises blending oils containing, respectively, sour and corrosive sulphur, and subjectin the mixture to the action of sodium plum ite.

2. The method of treating mineral oil containing sour sulphur, which comprises blending therewith a mineral oil containing corrosive sulphur, and subjecting the mixture to the action of sodium plumbite.

3. The method of treating mineral oil plumbites.

containing sour sulphur, which comprises blending therewith an artificial solution of corrosive sulphur in oil, and subjectin the mixture to the action of sodium plumbite.

. 4. The method of treating mineral oil to reduce the sour sulphur and excess corrosive sulphur contents, which comprises blending with the oil to be treated an oil containing sour sulphur, subjecting the mixture to the action 0 sodium plumbite to form with the sour sulphur of both oils reaction products in quantity sufficient to react with substantially all of the corrosive sulphur present.

5. The method of treating mineral oil to reduce the sour sulphur and excess corrosive sulphur contents, which comprises blending with the oil to be treated an oil containing corrosive sulphur and an excess of sour su1- phur, subjectin the mixture to the action of sodium plumbite to form with the sour sulphur of both oils reaction products in quantity sufiicient to react with substantially all of the corrosive sulphur present.

6. The method of treating mineral oil to reduce its corrosive sulphur and excess sour sulphur contents, whichcomprises blending with the oil to be treated an oil containing corrosive sulphur, subjecting the mixture to the action of sodium plumbite to form with the sour sulphur of both oils reaction prodnets in quantity sufficient to react with substantially all of the corrosive sulphur present.

In testimony whereof I have hereunto affixed my signature this28 day of April, 1923.

ERNST M. JOHANSEN. 

